Azo compounds having a 3-arylthio- or aliphaticthio-4-cyano- or alkoxycarbonyl-pyrazolyl-5 diazo component radical

ABSTRACT

Disclosed are azo dyes of the formula ##STR1## wherein R 1  is an aliphatic or aryl group, 
     R 2  is cyano, alkoxycarbonyl or substituted alkoxycarbonyl, 
     R 3  is an aliphatic or aryl group, and 
     K is a coupling component radical, 
     The synthesis thereof and the use thereof for the dyeing and printing of textile and non-textile substrates. The disclosed disperse dyes are useful for dyeing and printing synthetic and semi-synthetic, hydrophobic, high molecular weight materials such as linear aromatic polyesters, polyamides, cellulose 21/2 acetate and cellulose triacetate. The obtained dyeings have satisfactory fastness properties, particularly fastness to light, thermofixation, sublimation and pleating.

The invention relates to azo compounds.

The invention provides azo dyestuffs having, as radical derived from a diazo component, a radical of formula I, ##STR2## in which R₁ and R₃, independently, are aromatic or aliphatic residues, and

R₂ is cyano or an alkoxycarbonyl radical.

As will be apppreciated, the invention is based on the discovery of azo dyestuffs having the novel radical of formula I as the radical derived from a diazo component. Such dyestuffs may belong to the well recognized classes of dyestuffs, depending on substituents borne by the radical of formula I or by the coupling component in the dye molecule. Conversely, the radical of formula I may bear as the aromatic or aliphatic residues as R₁ and R₃ and as substituents on the alkoxycarbonyl radical as R₂ such residues and substituents as are common in the azo dye art, having regard to the ultimate utility to which the dyestuff is intended to be put or the class of dyestuff desired. Of particular interest are disperse dyes bearing the radical of formula I. Particularly for this class of dyestuff, any aliphatic residue as R₁ and R₃ is, preferably, an unsubstituted alkenyl radical of 2 to 4 carbon atoms, such as the allyl radical, or, more particularly, an alkyl radical, preferably of 1 to 4 carbon atoms, unsubstituted or substituted by a substituent selected from hydroxy, cyano, C₁₋₄ alkoxy, phenyl, phenoxy, chlorine or bromine, any aromatic residue as R₁ or R₃ being, preferably, phenyl, unsubstituted or substituted by up to a total of three substituents selected from chlorine, bromine and methyl (up to three thereof), methoxy, ethoxy, cyano and nitro (up to two thereof) and methoxycarbonyl, ethoxycarbonyl, aminosulphonyl and mono- or di-C₁₋₄ alkylaminosulphonyl (up to one thereof) and any alkoxycarbonyl radical as R₂ being, preferably, unsubstituted and having from 1 to 4 carbon atoms in the alkoxy moiety.

The compounds provided by the invention can be represented by the formula ##STR3## where R₁ to R₃ are as defined above, and

K is the radical of a coupling component.

Preferred radicals of formula I, particularly for disperse dyes, are the radicals of formula I', ##STR4## in which R₁ ' is C₁₋₄ alkyl or phenyl; preferably methyl, ethyl or phenyl; most preferably methyl,

R₂ ' is cyano or (C₁₋₄ aloxy) carbonyl preferably cyano, methoxycarbonyl or ethoxycarbonyl; most preferably cyano, and

R₃ ' is methyl, unsubstituted phenyl or phenyl substituted by up to two substituents selected from chlorine, bromine, methyl and methoxy; preferably methyl or phenyl; most preferably phenyl.

As regards coupling components for monoazo dyestuffs, and particularly for disperse dyestuffs, such may be any common in the art, for example, N-alkyl- and N,N-dialkyl-aminobenzene, α-(N-alkyl)- or α-(N,N-dialkyl)-aminonaphthalene, pyrazolone, 5-aminopyrazole and 3-cyano-4-alkyl-6-hydroxypyridone-2 derivatives, in which the alkyl radicals are preferably of 1 to 4 carbon atoms. The preferred coupling component radicals are 4-N-β-C₁₋₄ alkoxycarbonylethylaminonaphthyl-1, 1-C₁₋₄ alkyl-3-cyano-4-methyl-6-hydroxypyridone-2-yl-5, 1-phenyl-3-methylpryazolon-5-yl-4 and 1-phenyl-3-methyl-5-aminopyrazolyl-4 radicals and radicals of formula II, ##STR5## in which R₄ is hydrogen, chlorine, bromine, cyano, C₁₋₂ -alkyl, formylamino, an unsubstituted C₁₋₄ alkylcarbonylamino, C₁₋₄ alkoxycarbonylamino, β-C₁₋₄ alkoxyethoxycarbonylamino or C₁₋₄ alkylsulphonylamino radical, or one of such latter four radicals substituted in the terminal alkyl moiety by a substituent selected from chlorine, bromine, cyano, C₁₋₄ -alkoxy, phenyl and phenoxy; R₄ preferably being acetylamion, propionylamino, methoxycarbonylamino, ethoxycarbonylamino, β-methoxyethoxycarbonylamino or β-ethoxy-ethoxycarbonylamino

R₅ is hydrogen of C₁₋₄ alkoxy, preferably hydrogen or ethoxy,

either R₆ is C₂₋₄ alkenyl; 4-nitrophenyl; unsubstituted C₁₋₄ alkyl; C₁₋₄ alkyl monosubstituted by chlorine, bromine, cyano, hydroxy, C₁₋₄ alkoxy, C₁₋₄ alkoxycarbonyl, β-C₁₋₄ -alkoxyethoxycarbonyl, C₁₋₄ alkoxycarbonyloxy or C₁₋₄ alkylcarbonyloxy; or C₁₋₄ alkyl disubstituted, once by hydroxy and once by one of the aforesaid substituents;

R₆ preferably being ethyl, unsubstituted or substituted by cyano, hydroxy, methoxy, ethoxy, acetoxy, propionyloxy, methoxycarbonyl or ethoxycarbonyl,

and R₇ has one of the significances of R₆, hydrogen, phenyl-(C₁₋₄)alkyl, a group of formula (a) to (d) ##STR6## preferably ethyl, unsubstituted or substituted by cyano, hydroxy, methoxy, ethoxy, acetoxy, propionyloxy, methoxycarbonyl or ethoxy-carbonyl,

or R₆ and R₇, together, form a group of formula (e)

    --CH.sub.2 CH.sub.2 SO.sub.2 CH.sub.2 CH.sub.2 --,         (e)

with the provisos that, in the radical of formula II, (i) any alkyl radical or moiety substituted by hydroxy, alkoxy, alkoxycarbonyloxy phenoxy or alkylcarbonyloxy, is of at least two carbon atoms, the substituent not being in α-position, and (ii) R₆ and R₇ do not simultaneously signify 4-nitrophenyl radicals or tertiary butyl radicals.

Thus, the preferred compounds of this application are the compounds of Formula Ia wherein

each of R₁ and R₃ is independently C₂₋₄ alkenyl; C₁₋₄ alkyl; C₁₋₄ alkyl monosubstituted by hydroxy, cyano, C₁₋₄ alkoxy, phenyl, phenoxy, chloro or bromo; phenyl or substituted phenyl having 1 to 3 substituents each of which is independently chloro, bromo, methyl, methoxy, ethoxy, cyano, nitro, methoxycarbonyl, ethoxycarbonyl, sulfamoyl, C₁₋₄ alkylsulfamoyl or di-(C₁₋₄ alkyl)sulfamoyl, with the proviso that the maximum number of substituents selected from the group consisting of methoxy, ethoxy, cyano and nitro is two and the maximum number of substituents selected from the group consisting of methoxycarbonyl, ethoxycarbonyl, sulfamoyl, C₁₋₄ alkylsulfamoyl and di-(C₁₋₄ alkyl)sulfamoyl is one,

R₂ is cyano or (C₁₋₄ alkoxy)carbonyl, and

K is 4-N-β-(C₁₋₄ alkoxy)carbonylethylaminonaphthyl-1,1-C₁₋₄ alkyl-3-cyano-4-methyl-6-hydroxypyridon-2-yl-5, 1-phenyl-3-methylpyrazolon-5-yl-4, 1-phenyl-3-methyl-5-aminopyrazolyl-4 or ##STR7## wherein R₄ is hydrogen; chloro; bromo; cyano; C₁₋₂ alkyl; formamido; (C₁₋₄ alkyl)carbonylamino; (C₁₋₄ alkyl)carbonylamino the C₁₋₄ alkyl radical of which is monosubstituted by chloro, bromo, cyano, C₁₋₄ alkoxy, phenyl or phenoxy; (C₁₋₄ -alkoxy)carbonylamino; (C₁₋₄ alkoxy)carbonylamino the C₁₋₄ alkoxy radical of which is monosubstituted by chloro, bromo, cyano, C₁₋₄ alkoxy, phenyl or phenoxy; β-(C₁₋₄ alkoxy)ethoxycarbonylamino; β-(C₁₋₄ alkoxy)ethoxycarbonylamino the C₁₋₄ alkoxy moiety of which is monosubstituted by chloro, bromo, cyano, C₁₋₄ alkoxy, phenyl or phenoxy; C₁₋₄ alkylsulfonylamino or C₁₋₄ alkylsulfonylamino the C₁₋₄ alkyl radical of which is monosubstituted by chloro, bromo, cyano, C₁₋₄ alkoxy, phenyl or phenoxy,

R₅ is hydrogen or C₁₋₄ alkoxy,

R₆ is C₂₋₄ alkenyl; 4-nitrophenyl; C₁₋₄ -alkyl or substituted C₁₋₄ alkyl having 1 or 2 substituents each of which is independently chloro, bromo, cyano, hydroxy, C₁₋₄ alkoxy, (C₁₋₄ alkoxy)carbonyl, β-(C₁₋₄ alkoxy)ethoxycarbonyl, (C₁₋₄ alkoxy)carbonyloxy or (C₁₋₄ alkyl)carbonyloxy, with the proviso that when R₆ is disubstituted C₁₋₄ alkyl, at least one of the substituents is hydroxy,

R₇ is hydrogen; phenyl(C₁₋₄ alkyl); C₂₋₄ -alkenyl; 4-nitrophenyl; C₁₋₄ alkyl; substituted C₁₋₄ alkyl having 1 or 2 substituents each of which is independently chloro, bromo, cyano, hydroxy, C₁₋₄ -alkoxy, (C₁₋₄ alkoxy)carbonyl, β-(C₁₋₄ -alkoxy)ethoxycarbonyl, (C₁₋₄ alkoxy)carbonyloxy or (C₁₋₄ alkyl)carbonyloxy, with the proviso that when R₇ is disubstituted C₁₋₄ alkyl, at least one of the substituents is hydroxy; ##STR8## with the proviso that R₆ and R₇ are not simultaneously 4-nitrophenyl or t-butyl, or

R₆ and R₇ taken together are --CH₂ CH₂ SO₂ CH₂ CH₂ --,

with the proviso that any alkyl or alkoxy radical substituted by hydroxy, alkoxy, alkoxycarbonyloxy, phenoxy or alkylcarbonyloxy has more than one carbon atom and is not substituted in its β-position.

The preferred compounds of this group are those wherein the diazo component radical is a radical of Formula I'.

More preferred are the compounds of Formula Ia wherein

R₁ is methyl, ethyl or phenyl,

R₂ is cyano, methoxycarbonyl or ethoxycarbonyl,

R₃ is methyl or phenyl, and ##STR9## wherein R₄ ' is acetamido, propionamido, methoxycarbonylamino, ethoxycarbonylamino, β-methoxyethoxycarbonylamino or β-ethoxyethoxycarbonylamino,

R₅ ' is hydrogen or ethoxy, and

each of R₆ ' and R₇ ' is independently ethyl or ethyl monosubstituted by cyano, hydroxy, methoxy, ethoxy, acetoxy, propionyloxy, methoxycarbonyl or ethoxycarbonyl.

The invention also provides a process for the production of azo dyes having, as radical derived from a diazo component, a radical of formula I, stated above, which process comprises coupling, with an appropriate coupling component, a diazo derivative of an amine of formula III, ##STR10## in which R₁ to R_(d) are as defined above.

The above process may be carried out in conventional manner.

The amines of formula III are either known, e.g. from Chem. Ber. 95 2881 et. seq. (1962), or may be produced in manner analogous thereto from available starting materials.

Depending on the classes to which the azo dyes according to the invention belong, they may be employed for the dyeing or printing of a wide variety of textile and non-textile substrates, the classes to which particular dyestuffs belong, the substrates dyeable therewith and the methods of dyeing being within the skill of the man in the art.

The disperse dyes provided by the invention may be employed to dye substrates conventionally dyeable using disperse dyes, i.e. of fully or semi-synthetic hydrophobic, high-molecular weight materials, e.g. textile substrates comprising or consisting of linear, aromatic polyester, of cellulose 21/2 acetate, cellulose triacetate or of synthetic polyamide. Such substrates may be dyed in conventional manner, e.g. by the method described in French Pat. No. 1,445,371. The dyeings obtained, particularly with the preferred compounds, have satisfactory overall fastness properties, particularly to light, thermofixation, sublimation and pleating. Other fastness properties may also be mentioned, e.g. wet fastness (water, washing and perspiration), fastness to solvents (dry-cleaning solvents), lubricants, rubbing, cross-dyeing, ozone, flue gases and chlorine. They show a resistance to permanent press processes and soil-release finishing. The dyes show good dischargeability, resistance to reduction (when dyeing wool containing substrates) and they reserve wool and cotton.

Prior to using the disperse dyes for dyeing, they are conveniently converted into dyeing preparations employing conventional techniques such as grinding in the presence of dispersing agents and/or fillers, followed by vacuum or spray drying.

The following Examples, in which the temperatures are in degrees centigrade and the parts are in parts by weight, illustrate the invention.

EXAMPLE 1

11.5 Parts of 1-phenyl-3-methylmercapto-4-cyano-5-aminopyrazole are slowly added at 0°, with stirring, to a mixture consisting of 200 parts water and 160 parts concentrated sulphuric acid. The whole is stirred for half an hour, 4 parts sodium nitrite are added, stirring is then continued for a further 3 hours at 0°, the excess sodium nitrite is broken down with a little amidosulphonic acid and the mixture is filtered.

A solution is prepared from 30 parts 1-acetylamino-3-(N-β--cyanoethyl-N--β-acetoxyethyl)-aminobenzene and 100 parts glacial acetic acid, cooled to 0° and the diazonium solution which has also been cooled to 0° is added slowly with stirring.

The red dye of the formula ##STR11## which forms is briefly stirred, then filtered, washed with water until free from acid and dried.

It dyes polyester fibre material in brilliant red shades and the dyeings have notable fastness properties.

The following table gives other dyes of formula V ##STR12## which can be produced in analogous manner.

Also given is the shade which these dyes produce on polyester fibre material.

    TABLE               Shade on poly- Ex.        ester fibre No.  R.sub.1  R.sub.2      R.sub.3  R.sub.4 R.sub.5  R.sub.6       R.sub.7 material                                 2 C.sub.2 H.sub.5 CN      CH.sub.3 NHCOCH.sub.3 OC.sub.2 H.sub.5 CH.sub.2 CH.sub.2 OCOCH.sub.3      CH.sub.2 CH.sub.2 OCOCH.sub.3 violet 3 CH.sub.3 COOCH.sub.3 C.sub.6      H.sub.5  " H C.sub.2 H.sub.5 C.sub.2 H.sub.5 red 4  " CN  " NHSO.sub.2      CH.sub.3 H  " CH.sub.2 CH.sub.2 CN " 5  " COOC.sub.2 H.sub.5       " NHCOOCH.sub.2 CH.sub.2 OCH.sub.3 H  " CH.sub.2 CH.sub.2 OCOCH.sub.3 "      6 C.sub.6 H.sub.5 COOC.sub. 4 H.sub.9       " H H CH.sub.2CHCH.sub.2 CH.sub.2CHCH.sub.2 scarlet 7 CH.sub.3 COOC.sub.      3 H.sub.7  " NHCHO H C.sub.3 H.sub.7 C.sub.3 H.sub.7 red 8  " CN       ##STR13##       CH.sub.3 H C.sub.4 H.sub.9 C.sub.4 H.sub.9 scarlet 9  "       "      ##STR14##       NHCOOCH.sub.2 CH.sub.2 OC.sub.2 H.sub.5 H CH.sub.2 CH.sub.2 OCOC.sub.2      H.sub.5 CH.sub.2 CH.sub.2 CN red 10  "       "      ##STR15##       NHCOCH.sub.2 CH.sub.2 Cl H CH.sub.2 CH.sub.2 OCOCH.sub.3  " " 11  "  "       ##STR16##       NHCOCH.sub.2 CH.sub.2 Br H  "  " " 12  "       "      ##STR17##       NHCOCH.sub.2 CN H C.sub.2 H.sub.5 C.sub.2 H.sub.5 " 13  "  " C.sub.6      H.sub.5 NHCOCH.sub.2 C.sub.6 H.sub.5 OCH.sub.3 CH.sub.2 CH.sub.2 OH      CH.sub.2 CH.sub.2 OH red 14 CH.sub.3 CN C.sub.6 H.sub.5 Cl H CH.sub.2      CH.sub.2 OCOOC.sub.2 H.sub.5 CH.sub.2 CH.sub.2 OCOOC.sub.2 H.sub.5      scarlet 15  "       "      ##STR18##       Br H CH.sub.2 CH.sub.2 COOCH.sub.3 CH.sub.2 CH.sub.2 COOCH.sub.3 " 16      "  " C.sub.6 H.sub.5 CN H CH.sub.2 CH.sub.2 COOC.sub.4 H.sub.9 CH.sub.2      CH.sub.2 COOC.sub.4 H.sub.9 scarlet 17  "  "  " NHCOCH.sub.2 OC.sub.6      H.sub.5 H CH.sub.2 CHOHCH.sub.2 OH CH.sub.2 CHOHCH.sub.2 OH red 18  "  "       ##STR19##       NHCOC.sub.3 H.sub.7 H CH.sub.2 CH.sub.2 CN    H " 19  "  " C.sub.2      H.sub.5    H H C.sub.2 H.sub.5 CH.sub.2 CH.sub.2 C.sub.6 H.sub.5 scarlet      20  " COOCH.sub.3  "    H H  " CH.sub.2 C.sub.6 H.sub.5 " 21  "  "  "      NHCOCH.sub.3 H CH.sub.2 CH.sub.2 Cl CH.sub.2 CH.sub.2 Cl red 22  "  "  "       " H CH.sub.2 CH.sub.2 Br CH.sub.2 CH.sub.2 Br " 23  " COOC.sub.2      H.sub.5 CH.sub.3 CH.sub.3 H CH.sub.2 CH.sub.2 CN CH.sub.2 CH.sub.2 CN      scarlet 24  "  "  "  NHCOCH.sub.3 H CH.sub.2 CH.sub.2 OCH.sub.3 CH.sub.2      CH.sub.2 OCH.sub.3 red 25 CH.sub. 3 COOC.sub.2 H.sub.5 CH.sub.3    H H      CH.sub.2 CH.sub.2 OC.sub.2 H.sub.5 CH.sub.2 CH.sub.2 OC.sub. 2 H.sub.5      scarlet 26 C.sub.2 H.sub.5 CN  "    H H C.sub.2 H.sub.5 CH.sub.2      CH.sub.2 OC.sub.6 H.sub.5 " 27  "  "  "    H H       "      ##STR20##       " 28  "  " C.sub.6 H.sub.5 NHCOCH.sub.3 H  " 28  "  " C.sub.6 H.sub.5      NHCOCH.sub.3 H  " C.sub.2 H.sub.5 red 29  "  "  " NHCOC.sub.2 H.sub.5 H      "  " " 30  "  "  " NHCOCH.sub.2 CH.sub.2 Cl H  "  " " 31 CH.sub. 3  "  " N      HCOOCH.sub.2 CH.sub.2 OC.sub.2 H.sub.5 H  "  " " 32  "  "       " NHCOCH.sub.3 H CH.sub.2 CH.sub.2 CN CH.sub.2 CH.sub.2 OH " 33  "  "      "  " H  "    H " 34  "  "  "    H H C.sub.2 H.sub.5 C.sub.2 H.sub.5      scarlet 35  "  "  "    H H  " CH.sub.2 CH.sub.2 CN " 36  "  "  "    H H      CH.sub.2 CH.sub.2 CN  " " 37  "  "  " CH.sub.3 H "  " " 38 CH.sub.3 CN      C.sub.6 H.sub. 5 CH.sub.3 H CH.sub.2 CH.sub.2 CN CH.sub.2CH.sub.2      OCOCH.sub.3 scarlet 39  "  "  "    H H  " CH.sub.2 CH.sub.2 OCOCH.sub.3      " 40  "  "  " NHCOCH.sub.3 OC.sub.2 H.sub.5 CH.sub.2 CH.sub.2       OCOCH.sub.3  " red 41  "  "  "    H H C.sub.2 H.sub.5 CH.sub.2 CH.sub.2      OC.sub.6 H.sub.5 scarlet 42  "  "  " NHCOC.sub.2 H.sub.5 H CH.sub.2      CH.sub.2 OCOCH.sub.3 CH.sub.2 CH.sub.2 OCOCH.sub.3 red 43  "  "  "    H      H CH.sub.2 CH.sub.2 OH CH.sub.2 CH.sub.2 CN scarlet 44  "  "  "    H H       ##STR21##          H " 45  "  "  " NHCOCH.sub.3 H C.sub.2 H.sub.5 CH.sub.2 CH.sub.2      COOCH.sub.3 red 46  "  "  " NHCOC.sub.2 H.sub.5 H CH.sub.2 CH.sub.2 CN      CH.sub.2 CH.sub.2 OCOC.sub.2 H.sub.5 " 46a  "  "  "  " H C.sub.2 H.sub.5 C      H.sub.2 CH.sub.2 COOC.sub.2       H.sub.5 "

Following the procedure of Example 1 and employing appropriate starting materials, the following compounds, in which D is ##STR22## may be prepared.

    __________________________________________________________________________     Example No.                          Shade                                     __________________________________________________________________________     47                                                                                     ##STR23##                    violet                                    48                                                                                     ##STR24##                    yellow                                    49                                                                                     ##STR25##                    "                                         50                                                                                     ##STR26##                    orange                                    51                                                                                     ##STR27##                    "                                         52                                                                                     ##STR28##                    scarlet                                   53                                                                                     ##STR29##                    "                                         54                                                                                     ##STR30##                    "                                         55                                                                                     ##STR31##                    red                                       56                                                                                     ##STR32##                    scarlet                                   57                                                                                     ##STR33##                    "                                         58                                                                                     ##STR34##                    "                                         __________________________________________________________________________

application example

7 parts of the dye produced according to Example 1, together with 4 parts dinaphthyl methane disulphonic acid (sodium salt) 4 parts sodium cetyl sulphate and 5 parts anhydrous sodium sulphate, are ground in a ball mill for 48 hours to give a fine powder.

1 Part of the dye preparation thus obtained is made into a paste with a little water, and the resultant suspension is passed through a sieve into a dyebath containing 3 parts sodium lauryl sulphate in 4000 parts water. The liquor ratio is 1:40. 100 Parts scoured polyester fibre material are then added to the bath at 40°-50°, followed by 20 parts of a chlorinated benzene, emulsified in water, the bath is heated slowly to 100° and dyeing is carried out for 1-2 hours at 95°-100°. The brilliant-red dyed fibres are washed, soaped, washed again and dried. The level dyeing obtained shows fastness to light, cross-dyeing, washing, water, sea water, perspiration, sublimation, flue gas, thermofixation, pleating and permanent pressing. 

What is claimed is:
 1. A monoazo dye of the formula ##STR35## wherein each of R₁ and R₃ is independently C₂₋₄ alkenyl; C₁₋₄ alkyl; C₁₋₄ alkyl monosubstituted by hydroxy, cyano, C₁₋₄ alkoxy, phenyl, phenoxy, chloro or bromo; phenyl or substituted phenyl having 1 to 3 substituents each of which is independently chloro, bromo, methyl, methoxy, ethoxy, cyano, nitro, methoxycarbonyl, ethoxycarbonyl, sulfamoyl, C₁₋₄ alkylsulfamoyl or di-(C₁₋₄ alkyl)sulfamoyl, with the proviso that the maximum number of substituents selected from the group consisting of methoxy, ethoxy, cyano and nitro is two and the maximum number of substituents selected from the group consisting of methoxycarbonyl, ethoxycarbonyl, sulfamoyl, C₁₋₄ alkylsulfamoyl and di-(C₁₋₄ alkyl)sulfamoyl is one,R₂ is cyano or (C₁₋₄ alkoxy)carbonyl, and K is a coupling component radical of the N-alkyl-aminobenzene, N,N-dialkylaminobenzene, α-N-alkyl-aminonaphthalene, α-N,N-dialkylaminonaphthalene, pyrazolone, 5-aminopyrazole or 3-cyano-4-alkyl-6-hydroxypyridone-2 series.
 2. A compound of the formula ##STR36## wherein each of R₁ and R₃ is independently C₂₋₄ alkenyl; C₁₋₄ alkyl; C₁₋₄ alkyl monosubstituted by hydroxy, cyano, C₁₋₄ alkoxy, phenyl, phenoxy, chloro or bromo; phenyl or substituted phenyl having 1 to 3 substituents each of which is independently chloro, bromo, methyl, methoxy, ethoxy, cyano, nitro, methoxycarbonyl, ethoxycarbonyl, sulfamoyl, C₁₋₄ alkylsulfamoyl or di-(C₁₋₄ alkyl)sulfamoyl, with the proviso that the maximum number of substituents selected from the group consisting of methoxy, ethoxy, cyano and nitro is two and the maximum number of substituents selected from the group consisting of methoxycarbonyl, ethoxycarbonyl, sulfamoyl, C₁₋₄ alkylsulfamoyl and di-(C₁₋₄ alkyl)sulfamoyl is one,R₂ is cyano or (C₁₋₄ alkoxy)carbonyl, and K is 4-N-β-(C₁₋₄ alkoxy)carbonylethylaminonaphthyl-1, 1-C₁₋₄ alkyl-3-cyano-4-methyl-6-hydroxypyridon-2-yl-5, 1-phenyl-3-methylpyrazolon-5-yl-4, 1-phenyl-3-methyl-5-aminopyrazolyl-4 or ##STR37## wherein R₄ is hydrogen; chloro; bromo; cyano; C₁₋₂ alkyl; formamido; (C₁₋₄ alkyl)carbonylamino; (C₁₋₄ alkyl)carbonylamino the C₁₋₄ alkyl radical of which is monosubstituted by chloro, bromo, cyano, C₁₋₄ alkoxy, phenyl or phenoxy; (C₁₋₄ alkoxy)carbonylamino; (C₁₋₄ alkoxy)carbonylamino the C₁₋₄ alkoxy radical of which is monosubstituted by chloro, bromo, cyano, C₁₋₄ alkoxy, phenyl or phenoxy; β-(C₁₋₄ alkoxy)ethoxycarbonylamino; β-(C₁₋₄ alkoxy)ethoxycarbonylamino the C₁₋₄ alkoxy moiety of which is monosubstituted by chloro, bromo, cyano, C₁₋₄ alkoxy, phenyl or phenoxy; C₁₋₄ alkylsulfonylamino or C₁₋₄ alkylsulfonylamino the C₁₋₄ alkyl radical of which is nonosubstituted by chloro, bromo, cyano, C₁₋₄ alkoxy, phenyl or phenoxy, R₅ is hydrogen or C₁₋₄ alkoxy, R₆ is C₂₋₄ alkenyl; 4-nitrophenyl; C₁₋₄ -alkyl or substituted C₁₋₄ alkyl having 1 or 2 substituents each of which is independently chloro, bromo, cyano, hydroxy, C₁₋₄ alkoxy, (C₁₋₄ alkoxy)carbonyl, β-(C₁₋₄ alkoxy)ethoxycarbonyl, (C₁₋₄ alkoxy)carbonyloxy or (C₁₋₄ alkyl)carbonyloxy, with the proviso that when R₆ is disubstituted C₁₋₄ alkyl, at least one of the substituents is hydroxy, R₇ is hydrogen; phenyl(C₁₋₄ alkyl); C₂₋₄ -alkenyl; 4-nitrophenyl; C₁₋₄ alkyl; substituted C₁₋₄ alkyl having 1 or 2 substituents each of which is independently chloro, bromo, cyano, hydroxy, C₁₋₄ -alkoxy, (C₁₋₄ alkoxy)carbonyl, β-(C₁₋₄ -alkoxy)ethoxycarbonyl, (C₁₋₄ alkoxy)carbonyloxy or (C₁₋₄ alkyl)carbonyloxy, with the proviso that when R₇ is disubstituted C₁₋₄ alkyl, at least one of the substituents is hydroxy; ##STR38## with the proviso that R₆ and R₇ are not simultaneously 4-nitrophenyl or t-butyl, or R₆ and R₇ taken together are --CH₂ CH₂ SO₂ CH₂ CH₂ --, with the proviso that any alkyl or alkoxy radical substituted by hydroxy, alkoxy, alkoxycarbonyloxy, phenoxy or alkylcarbonyloxy has more than one carbon atom and is not substituted in its α-position.
 3. A compound according to claim 2 wherein K is 4-N-β-(C₁₋₄ alkoxy)carbonylethylaminonaphthyl-1.
 4. A compound according to claim 2 wherein K is 1-C₁₋₄ alkyl-3-cyano-4-methyl-6-hydroxypyridon-2-yl-5.
 5. A compound according to claim 2 wherein K is 1-phenyl-3-methylpyrazolon-5-yl-4.
 6. A compound according to claim 2 wherein K is 1-phenyl-3-methyl-5-aminopyrazolyl-4.
 7. A compound according to claim 2 wherein K is ##STR39##
 8. A compound according to claim 7 whereinR₄ is acetamido, propionamido, methoxycarbonylamino, ethoxycarbonylamino, β-methoxyethoxycarbonylamino or β-ethoxyethoxycarbonylamino, R₅ is hydrogen or ethoxy, and each of R₆ and R₇ is independently ethyl or ethyl mono-substituted by cyano, hydroxy, methoxy, ethoxy, acetoxy, propionyloxy, methoxypcarbonyl or ethoxycarbonyl.
 9. A compound according to claim 8 whereinR₁ is methyl, ethyl or phenyl, R₂ is cyano, methoxycarbonyl or ethoxycarbonyl, and R₃ is methyl or phenyl.
 10. A compound according to claim 2 whereinR₁ is C₁₋₄ alkyl or phenyl, R₂ is cyano or (C₁₋₄ alkoxy)carbonyl, and R₃ is methyl, phenyl or substituted phenyl having 1 or 2 substituents each of which is independently chloro, bromo, methyl or methoxy.
 11. A compound according to claim 10 whereinR₁ is methyl, ethyl or phenyl, R₂ is cyano, methoxycarbonyl or ethoxycarbonyl, and R₃ is methyl or phenyl.
 12. A compound according to claim 11 having the formula ##STR40## wherein K' is ##STR41##
 13. The compound according to claim 12 having the formula ##STR42##
 14. The compound according to claim 12 having the formula ##STR43## 